Improvement in pump-pistons



m P. GHFARD.

Pump Pistons.

v .Patented Jan. 16, 1872.

un m n UNITED STATEs ATENT OEEioE.

1 PAUL GTEEAED, or PAEIs, FRANCE.

IMPROVEMENT IN PUMP-PISTONS.

Specification forming part of Letters Patent No. 122,825, dated January 16, 1872.

To all whom it may concern:

Be it known that I, PAUL GIEFARD, of Paris, in the Republic of France, have invented a new Improvement in Pistons of Pumps and other Machinery, and I do hereby declare the following, when taken in connection with the accompanying drawing and the letters of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawing constitutes part of this specification and represents, in

Figure l, a side view of the piston, showing a section of the valve or packing; Fig. 2, an under-side view of the piston; Fig. 3, a central section ofthe piston as in its upward movement; Fig. 4, a central section of the piston as in its downward movement; Figs. 5, 6, 7, S, modiiications ofthe construction of the packing-ring or valve; Figs. 9, l0, l1, respectively, the reverse of Figs. l, 3, and 4; Figs. l2, 13, 14, views, showing the ring used only as a packing; and in Fig. 15, an illustration ofthe further use of this invention.

This invention relates to an improvement in pistons of pumps and like purposes; and it consists: First, in the employment oi a ring, washer, or disk of flexible material in an annular groove formed in the edge of the piston, performing the double part of valve and stop. Second, employing the pressure of the iiuid within the cylinder to expand the ring or washer, to counteract the wear, and to insure a perfect filling of the cylinder around the piston.

In the drawing I have represented three arrangements of my piston, which I will proceed to describe.

First arrangementpiston for compression or force downward, shown in Figs. 1,2,.91, and 4. The body of the piston c is formed of suitable material, and is of less diameter than the cylinder of the pump, in order to form a space for the admission of the luid through the piston. Its sides are hollowed out, having the form of a quarter of a circle for the insertion of the ring b, serving the purpose of a valve, as seen in section, Figs. 3 and 4. The ring b may be of any flexible material-by preference caoutchouc-and is held in the groove by a metallic disk, c, which is securely fastened to the body a of the piston by screwing or otherwise, thus forming an annular groove, within which the ring b rests. The diameter of the disk c is a little less than the diameter of tlfe cylinder. less in number, near its edge for the passage oi' iiuids, as seen in Fig. 2. The edge of the flexible ring b is slightly rounding at that point which is directly above the perforations o, as denoted in sections, Figs. 3 and 4.

The operation of the piston will be understood by reference to Figs. 3 and 4, which show the two positions of the ring b, according as the piston moves up or down. At the up-stroke, Fig. 3, the iiuid above the piston falls below, following the course denoted by the arrows. During its passage through the piston the iluid presses laterally upon the inside of the ring b, which rests upon the diskc and forces the ring hard against the cylinder, as seen in Fig. 3. This action or tendency to expand the ring is greater during the downward movement, because the iiuid is compressed and cannot escape through the piston to the upper part ofthe cylinder. The ring b is pressed with great force against the outside of the piston a. by the iuid which passes through the openings o in the disk and through the space between the upper edge of the piston and the cylinder. On the return stroke, as seen in Fig. 4, the ring b rises and closes the space between the upper'edge of the piston and cylinder, the iiuid pressing up against and within the ring to cause its expansion, as bei'ore described.

I will now describe my method of strengthening the ring b when I employ pistons of large diameter, as, for example, when applied to blast-engines. This arrangement is illustrated in Figs. 5, 6, 7, and 8. On the inside of the flexible washer b I make a groove, m, which serves to hold the ring p fitted thereon, the said ring formed of a strip of metal by preference steel. An oblique or diagonal out, n, in the washer b, and a straight cut, q, in the ring p, permit the expansion of the washer and ring to make a perfect joint between the piston and cylinder. The metal ring p, by its elasticity, permits the greater expansion of the washer, and also strengthens it and gives The disk has perforations o o, more or` -rst, the position of the parts being simply reto it a certain rigidity vertically, which prevents all liability of displacing the flexible material.

Second arrangement is for pistons of eX- haust-valves, and is illustrated in Figs. 9, 10, and 11. This arrangement is the same as the versed, and consequently the action is reversed.

Third arrangement is for what are termed solid pistons-that is, pistons through Which no passage of fluid occurs in either movement of the piston, as in double-actingforce-pumpsand is illustrated in Figs. 12, 13, 14. In this arrangement the action is concentrated in the Working or expanding of the ring, which, as is shown in Fig. 14, moves up and down, on the down stroke against the part a, and on the up stroke against-c, the parts a and c being of the same diameter, but of less diameter than the cylinder. The spaces formed between the outer surface of the piston and the inner surface of the ring permits the entrance of the fluid required to produce a circumferential pressure upon the inside of the ring.

structed substantially as described, so that the force applied to the fluid may cause the fluid to pass Within and so asto bear against the said ring to cause its expansion, substantially as specified.

In testilnon y whereof I have signed myname to this specification before two subscribing Witnesses.

PAUL GIFFARD.

Witnesses: v

J ULEs ARMENGAUD, C. LAFoUD. (118) 

